This invention relates to a lightweight mobile compressed gas module. This mobile module is for lightweight use and transport of large volumes of compressed gas in a compact mobile unit.
It is common practice for pressure vessels in the form of industrial gas cylinders to be manufactured with flat bottoms enabling the cylinders to stand upright for filling and general use. These industrial gas cylinders typically contain various gases under pressure (Argon, Acetylene, Nitrogen, Oxygen, etc.). The vast majority of the cylinders are constructed from steel and aluminum. These steel and aluminum pressure vessels are heavy and result in a low performance factor where the performance factor is defined as (PV)/W, where P=operating pressure, V=internal volume (water capacity), and W=weight of vessel at 0 psig.
It is common practice for these vessels to be transported to a site for use of the gas contained therein via an industrial type cart. These carts are designed for and function only as a temporary means of moving the cylinder from one location to another, usually from the fill station to the end use location. Heavy steel and aluminum pressure vessels are loaded and unloaded from the industrial cart once the delivery has been accomplished. Typically, the cylinders are temporarily supported to these industrial carts by a chain strapped around the cylinder or the cylinder is placed in a metal ring. Both of these designs scratch and damage the exterior of the pressure vessel which often, at a minimum, requires exterior refurbishment. Further, prior art carts are also heavy, reflecting the structural need to support a pressure vessel with poor performance factors, and these carts are also large and cumbersome and, in particular, do not lend themselves to being transported in automobiles. Therefore, for compressed gas applications that require a high level of transport and usage, the cylinder size must be reduced to reduce the weight to a manageable level for an individual to lift and move.
One example of this high usage and transport application of compressed gas is in the home medical oxygen market. The most common cylinder used in this application is what is called an xe2x80x9cExe2x80x9d cylinder which, due to the poor performance factor of steel and aluminum, provides only 24 cu. ft. of oxygen, or 2-4 hours of oxygen consumption. Due to this low capacity, in some cases as many as 12 cylinders are required at the consumer""s location to be rotated as the cylinder gas is consumed. These aluminum and steel cylinders typically weigh 8-10 lbs. each of which, in combination with an industrial type cart that weighs 4.5 lbs., results in a total average weight of 13.5 lbs.
In addition to the low capacity of the cylinders, the industrial carts utilized for transporting the cylinders are large, cumbersome, and inconvenient which greatly limits mobility. For example, these xe2x80x9cExe2x80x9d carts typically will not fit behind the seat of a car as a result of the cart having a fixed handle length for a total height of 39 inches. The cylinder is not fixed to the cart, such that the cylinder may fall out of the cart when placed on its side. This causes a problem when placed in the trunk of a car for travel wherein the cylinder may fall out of the cart resulting in the cylinder being free to roll around the trunk and possibly damage the valve on the top of the cylinder. These cylinders also have a high L/D ratio (L=length, D=diameter) which results in a cylinder or cylinder/cart that is very susceptible to tipping over. This is a common problem and has an inherent safety hazard of the valve being sheared off which will result in a dangerous rapid expansion of the compressed gas. These cylinder carts also require a large floor space due to this high L/D ratio, and is typically on the order of 113 in2.
Clearly a low profile (low L/D), lightweight, high capacity, compact, highly mobile compressed gas source is needed to address the above limitations.
The present invention provides a mobile compressed gas module including a frame having top and bottom horizontal members and a vertical member extending between the top and bottom horizontal members. A pressure vessel having a cylindrical side wall and hemispherical top and bottom polar ends is positioned between the top and bottom horizontal members.
The top and bottom horizontal members each define a proximal end and a distal end wherein the vertical member extends between the proximal ends, and the pressure vessel extends between the distal ends thereof.
The pressure vessel includes a lower fitting attached to the bottom polar end, and an upper fitting attached to the top polar end wherein the lower fitting is adapted to engage a lower cooperating structure at the bottom horizontal member for preventing horizontal or lateral movement of the bottom polar end of the pressure vessel relative to the bottom horizontal member. Similarly, the upper polar end of the pressure vessel includes an upper fitting attached thereto for engaging an upper cooperating structure at the top horizontal member for preventing horizontal or lateral movement of the top polar end relative to the top horizontal member.
The vertical member defines a generally planar structure which, in combination with the attached cylinder prevents the gas module from rolling if placed on its side. Further, the pressure vessel and vertical member define parallel structures extending between and rigidly engaged with the top and bottom horizontal members whereby the pressure vessel and vertical member combine to provide structural integrity for the compressed gas module.
The compressed gas module further includes a handle located at an upper end of the vertical member of the frame, and wheels which are located supported at the proximal end of the bottom horizontal member for permitting wheeled transport of the gas module. In addition, the handle is formed as a telescoping structure in order to permit the handle to be positioned at a convenient height for guiding the gas module on its wheels, and for positioning the handle at a low height to form a compact unit for storage and transportation of the gas module.
Therefore, it is an object of the present invention to provide a one-piece lightweight mobile compressed gas module which is easily transported, loaded, unloaded and lifted.
It is a further object of the invention to provide such a gas module which supplies a large volume of compressed gas.
It is another object of the invention to provide a mobile compressed gas module formed as a one-piece design comprised of a frame and pressure vessel wherein both the frame and pressure vessel are utilized as load carrying components contributing to the strength and stiffness of the gas module.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.